Fixture for and method of assembling heat exchanger core



Aug. 2, 1966 J, SMELTZER ET AL 3,263,314

FIXTURE FOR AND METHOD OF ASSEMBLING HEAT EXCHANGER CORE Filed June 5, l63 2 Sheets-Sheet 1 INVENTOR.

DAVID D. JORDAN PAUL J. SMELTZER.

AGENT.

Aug. 2, 1966 p. SMELTZER ET AL 3,263,314-

FIXTURE FOR AND METHOD OF ASSEMBLING HEAT EXCHANGER CORE Filed June 5,1963 2 Sheets-Shed 2- l N VEN'TOR.

DAVID. 0. JORDAN.

1 PA 21L .1. SMELTZER.

AGENT.

United States Patent 3,263,314 FIXTURE FOR AND METHOD OF ASSEMBLING HEATEXCHANGER CORE Paui J. Smeltzer, Pittsburgh, Pa., and David D. Jordan,South Bend, Ind., assignors to The Bendix Corporation, South Bend, Ind.,a corporation of Delaware Filed June 5, 1963, Ser. No. 285,663 4 Claims.((11. 29-1573) This invention relates, in general, to assembly fixturesand, in particular, to a fixture for assembling a compartmentized pellettube type heat exchanger core.

The assembly of a heat exchanger core having compartments filled with apellet matrix presents a problem in that the various compartmentsthrough which the tubes extend must be completely filled with pelletmaterial which, heretofore, has been accomplished by pouring the pelletsinto each compartment from an open end thereof before the componentsections of the core are inserted in position to define the adjacentcompartment. Such an arrangement is disadvantageous in that the assemblytime of the heat exchanger core is high with corresponding high laborcosts and the quantity of pellets poured into each compartment must becarefully controlled to permit proper positioning of the variouscomponent sections of the heat exchanger core.

It is therefore an object of the present invention to provide a fixturefor easy and quick assembly of a compartmentized pellet tube type heatexchanger core.

It is another object of the present invention to provide a fixture for acompartmentized pellet tube type heat exchanger core whereby the variouscompartments thereof are filled with the pellet material through aseparate access portion communicating with each of the compartments.

It is still another object of the present invention to provide a fixturefor a compartmentized pellet tube type heat exchanger core whereby thepellet material is introduced into the various compartments thereofsubsequent to the assembly of the various component sections of the corewhich together with the fixture define the various compartments.

Other objects and advantages of the present invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings wherein:

FIGURE 1 is a plan view of the present invention;

FIGURE 2 is a sectional view taken on line 22 of FIGURE 1 showing thecompartmentized pellet tube type heat exchanger core as assembled withinthe fixture;

FIGURE 3 is a view of the two halves of the fixture in separated form;

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 1;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 1;

FIGURE 6 is a sectional View taken on line 6--6 of FIGURE 1; and

FIGURE 7 is a view of the assembled compartmentized pellet tube typeheat exchanger core removed from the fixture.

Referring to the drawings, numeral 20 designates generally an assemblyfixture of cylindrical shape having two semicylindrical portions 22 and24 which are provided with spaced apart lugs 26 and 28, respectively,fixedly secured thereto. Each lug 26 has a bore 30 and a counterbore 32adapted to receive a locking pin 34 having a flanged portion 36 which isurged into engagement with lug 26 by a screw member 38 threadedlyengaged with one end of pin 34. The locking pin 34 is provided with aplurality of circumferentially spaced apart flutes 48 3,263,314 PatentedAugust 2, 1966 which are slidably carried by a bore 42 in lug 28. Thelugs 26 and 28 are secured together by a wedge shaped member 44 providedwith a slot 46 adapted to receive a reduced diameter section 48 oflocking pin 34, which member 44 is forced into position as shown inFIGURE 5 to thereby force lug 28 into locked engagement with lug 26.

A circular end plate 51) is held in clamped engagement with one end ofthe semicylindrical portions 22 and 24 by means of locking pins 52 whichextend through bores 54 in diametrically opposed lugs 56 fixedly securedto portions 22 and 24. The locking pins 52 extend through openings 58 inend plate 50 and are provided with reduced diameter portions 60 whichare received by slots 62 in associated wedge shaped members 64 which areforced into position as shown in FIGURE 2 to thereby force plate 50 intolocked engagement with lugs 56. Referring to FIGURES 2 and 4, the endplate 50 is provided with a plurality of locating pins 66 fixedlysecured thereto in circumferentially spaced apart relationship whichextend a predetermined distance longitudinally inwardly of thesemicylindrical portions 22 and 24 for a purpose to be explained. Aplurality of concentric annular rings 68 integral to end plate 50 extendtherefrom a predetermined distance longitudinally inwardly of thesemicylindrical portions 22 and 24 for a purpose to be explained. Aplurality of fluid access ports 76 located in the recesses defined byadjacent annular rings 68 extend through end plate 50 and permit fluidflow into and out of the recesses during a brazing operation to bedescribed. Also, fluid access ports 71 and 72 are provided in oppositeend sections of portion 28 to permit fluid flow into and out of theinterior of fixture 20 during the brazing operation.

A circular end plate 73 located at the opposite end of semicylindricalportions 22 and 24 is held in position within the inner walls of theportions 22 and 24 by a pair of diametrically opposed retaining members74 secured to portions 22 and 24 by bolts 76 threadedly engagedtherewith.

A support hook '78 is attached to a curved flexible bracket 80 havingopenings 82 at opposite end portions thereof adapted to receive pins 84fixedly secured to semicylindrical portions 22 and 24. A spring 86interposed between the end plate 73 and a retaining pin 88 fixedlysecured to hook 78 serves to load end plate 73.

The semicylindrical portion 24 is provided with a plurality of spacedapart boss portions 96 which are bored to provide circular loading ports92 having a counterbore 94. Each port 92 is adapted to receive a plug 96having a curved end portion 98 which conforms to the curvature of theinner wall of portion 24 and a flanged section 100 which fits intocounterbore 94. A pair of diametrically opposed locating pins 102 arefixedly secured to flanged section 100 and extend therefrom into slots104 formed in boss portions 90 to thereby locate plug 96 such that thecurved end portion 98 is aligned circumferentially with the inner curvedwall of portion 24. The plugs 96 are locked in position by overlappingretaining plates 106 secured to boss portions 90 by bolts 188.

The heat exchanger core generally indicated by numeral 110 includes anoutlet end plate 112 provided with a plurality of spaced apart openings114 through which extend a plurality of longitudinally extending tubes116. The opposite inlet end of the core 111 is provided with an inletend plate 118 which is provided with a plurality of openings 120 throughwhich the tube 116 extends. Spaced apart circular baflles 122 and 124are provided with extruded openings 126 through which the tubes 116extend. The baffles 122 and 124 are maintained in spaced apartrelationship relative to end plates 112 and 118, respectively, as wellas to one another by pairs of longitudinally extending perforatedV-shaped sheet metal plates 128 which are located radially outwardlyfrom the tubes 116. The adjacent parallel edges of each pair of plates128 are spaced circumferentially apart thereby partially definingrectangular openings 130 through which a pellet matrix 132 may beintroduced to fill chambers 134 partially defined by each pair of plates128. Battles 122 and 124 are severed to conform to one of the V-shapedplates 128 abutting thereagainst thereby providing an opening 136through which fluid may flow between adjacent chambers 134. The varioussections including the pellet matrix 132 of the heat exchanger core 110are coated with a suitable brazing material which under the applicationof heat flows around adjacent contacting surfaces of the core 110thereby providing a unitized structure.

The heat exchanger core 110 is assembled within the fixture 20 in thefollowing manner. The fixture 20 is partially assembled by placing thesemicylindrical portions 22 and 24 together with pins 34 extendingthrough the respective openings 42 and lugs 28. The wedge shaped members44 are driven into position on reduced diameter sections 48 to therebylock the portions 22 and 24 together. The end plate 50 is attached tothe one end of portions 22 and 24 by inserting locking pins 52 throughbores 54in lugs 56 and openings 58 in plate 50 and driving wedge shapedmembers 64 into position on reduced diameter sections 60 to thereby lockend plate 50 securely in position. The assembled portions 22 and 24 andend plate 50 are placed upright on end plate 50. The end plate 112 isplaced within the portions 22 and 24 where it rests against locatingpins 66. The two outermost rows of tubes 116 against which the plates128 bear are inserted into the two outermost rows of openings 114 andend plate 50. A plate 128 is inserted between each of the two outermostrows of tubes 116 and the adjacent inner wall defined by portions 22 and24 with one end of each plate 1'28 bearing against end plate 50. The twooutermost rows of tubes 116 are inserted through the correspondingopenings 126 of baflle 122 which is pushed longitudinally along tubes116 into engagement with the ends of the pair of plates 128 therebelow.A second pair of plates 128 is inserted between the two rows of tubes116 and the adjacent inner wall portions 122 and 124 with one end ofeach plate bearing against the upper surface of bafile 122. The tubes116 are inserted through corresponding openings 126 of baffle 124 whichis located with its severed portion which defines opening 136 onehundred and eighty degrees out of alignment with the correspondingsevered portion of baffle 122. The baffle 124 is pushed longitudinallyalong the tubes 116 into engagement with the ends of the second pair ofplates 128 therebelow. A third pair of plates 128 is inserted betweentubes 116 and the inner wall defined by port-ions 22 and 24 with theends thereof bearing against the upper surface of batfle 124. The tubes116 are inserted through corresponding openings 120 and end plate 118which is urged into engagement with the ends of plates 128 therebelow.The remaining tubes 116 are inserted through corresponding openings 120-in end plate 118 and pushed longitudinally through correspondingopenings in baflles 122 and 124 and end plate 112 into position with theends thereof abutting annular rings 68 in end plate 50. The end plate 73is inserted in position against end plate 118 and retaining members 74locked in position to retain end plates 73. It will be noted that therectangular openings 130 partially defined by adjacent parallel edges ofeach pair of plates 128 are aligned with associated loading ports 92through which the pellet matrix 132 is introduced to fill chambers 134.Also, as shown in FIGURE 2, the tubes 116 are located longitudinallyrelative to the end plates 112 and 118 by the annular rings 68 whichcontact the ends of tubes 116 such that the outlet ends of the tubes 116extend slightly below the end plate 112 and the inlet end of tubes 116are substantially flush with the one side of end plate 118. It will beunderstood that the various component sections which make up theassembled fixture 20 may be made of any suitable metal. However,applicants have found that stainless steel is well suited for such usein which case the fixture is oxidized to prevent the adherence ofbrazing material to the fixture 20 during the brazing operation wherebythe parts of the heat exchanger core are unitized. The fixture 20 ispositioned horizontally with loading ports 92 facing upward and thepellet matrix 132 poured through each of the ports 92 to fill thechambers 134. The filling of chambers 134 is facilitated by attachingsuitable vibrating mechanism, not shown, to the fixture 20 whichagitates the same to promote the flow of pellet matrix around the tubes116 and within chambers 134 thereby completely filling chambers 134 withpellet matrix. The pellet matrix 132 is allowed to partially fill theports 92. Each plug 96 is positioned in its respective loading port 92with pins 102 aligned with slots 104 and pushed inwardly to compress thepellet matrix 132 and allow pins 102 to engage slots 104. Each plug 96is locked in position by its associated retaining plate 106 which issecured by tightening bolts 108. In the locked position the curved endportion 98 of each plug 96 extends inwardly from the inner wall ofportion 28 a slight distance 'to insure that the pellet matrix 132 inthe region of ports 92 does not extend radially outwardly beyond theinner wall of portion 28.

The support hook 78 is secured to the above described assembled fixture20 by temporarily spreading the bracket to enable pins 84 to engageopenings 82.

The fixture 20 containing the assembled heat exchanger core 110 issubjected to a conventional brazing process which includes immersing thesame in a heated flux bath for a predetermined period of time to permitflux to flow through ports 71 and 72 into the interior of fixture 20thereby causing the brazing material on the heat exchanger core 11a toflow and join the component sections at the adjacent contacting surfacesthereof. The fixture 20 and core 110 is subsequently removed from theflux bath and the flux drained and rinsed theretfrom. Finally, thebracket 80 and end plates 50 and 72 are detached from semicylindricalportions 22 and 24 and Wedge shaped members 44 and 64 disengaged frompins 34 and 52, respectively, to permit separation of thesemicylindrical portions 22 and 24 and removal of the unitized heatexchanger core 110. The locking pins 34 are provided with the flutes 40to reduce the eflective engagement area of pins 34 and associated bores42 thereby reducing the tendency for pins 34 to adhere to lugs 44 due tobrazing material lodging therebetween.

The heat exchanger core 110 is adapted for insertion in a heat exchangercasing, not shown, having an inner diameter equivalent to the innerdiameter of fixture 20. The outermost edge of end plate 112 is adaptedto engage an O-ring seal, not shown, carried by the heat exchangercasing inner wall which O-ring provides a fluid seal. An O-ring seal,not shown, carried in a recess 138 in end plate 118 is adapted to engagethe inner wall of the heat exchanger casing to thereby provide a fluidseal. The heat exchanger casing, not shown, is provided with inlet andoutlet ports which direct a first fluid to and away from core 110 in thedirection shown by the arrows labeled In and Out in FIGURE 7. Theopenings 136 in bafiles 122 and 124 direct the first fluid in a tortuouspath from one end of core 110 to the opposite end thereof as indicatedby the remaining arrows. Also, the heat exchanger casing, not shown, isprovided with inlet and outlet conduits which direct a second fluid toand away rfrom tubes 116 through which the second fluid flows. The firstfluid may be the cooling medium and the second fluid may be the mediumto be cooled, or the first fluid the medium to be cooled and the secondfluid the cooling medium depending upon the direction of heattransferdesired.

It will be understood that various changes and modifications in thestructure shown and described may be made by those persons skilled inthe art without departing from the spirit of the present invention. Forinstance, the fixture is not restricted to cylindrical shaped heatexchanger cores and may be readily adapted for use with heat exchangercores of various other shapes.

We claim:

1. A fixture for assembling a heat exchanger core having a first fluidconducting compartment therein which is filled with pellet material anda plurality of tubes which extend through the compartment for conductinga second fluid through the core, said fixture comprising:

a two part housing having first and second portions removably securedtogether,

a first end plate removably secured to one end of said first and secondportions,

a second end plate removably secured to the opposite end of said firstand second portions,

said heat exchanger core being held in assembled position within saidhousing by said first and second end plates,

a loading port formed in the sidewall of one of said first and secondportions for introducing pellet material into the compartment of saidcore to fill the same, and

a plug removably secured to said loading port for retaining said pelletmaterial in the compartment during a brazing operation whereby thecomponent sections including said pellet material of said heat exchangercore are unitized,

said first and second end plates and said first and second portionsbeing disassembled after the brazing operation to permit removal of theunitized heat exchanger core.

2. A fixture for assembling a heat exchanger core having a plurality ofspaced apart baflles and end plates through which a plurality of spacedapart tubes extend, said bafiles and end plates being separated by aplurality of spacing members and partially defining a plurality ofcompartments adapted to be filled with pellet material, said fixturecomprising:

a two part housing having first and second semicylindrical portionsadapted to be removably secured together,

a first end plate removably secured to one end of said first and secondportions to close the same,

said two part housing being up ended with its opposite open end up topermit insertion of said end plates, spacing members, bafiles and tubesin predetermined position relative to one another therein,

a second end plate removably secured to said opposite open end to closethe same and hold the assembled end plates, spacing members and bafilesin spaced apart position longitudinally within said two part housing,

a separate loading port formed in the sidewall of one of said first andsecond semicylindrical portions and communicating with each of theplurality of compartments for introducing pellet material therein,

a plug removably secured in each of said loading ports for retaining thepellet material in the associated compartments during a brazingoperation whereby the component sections including said pellet materialare unitized,

said first and second semicylindrical portions and said first and secondend plates being disassembled after the brazing operation to permitremoval of the unitized heat exchanger core.

3. A method of making a tube type brazed heat exchanger core having endplates and bafiies intermediate thereof through which a plurality oftubes extend and which define a plurality of compartments adapted to befilled with pellet material comprising the steps of:

providing a fixture having a two part housing removably secured togetherto form a cavity closed at one end by an end plate removably secured tothe two part 6 housing and provided with a plurality of loading portsformed in the sidewall thereof,

placing the two part housing upright on the closed end thereof,

inserting a first end plate of said core in position within said twopart housing and inserting one end of the plurality of tubes in spacedapart openings formed in said first end plate,

inserting spacing members and bafiles spaced apart by said spacingmembers in order longitudinally within said two part housing to definethe plurality of compartments separated by said baflles andcommunieating with said loading ports,

inserting a second end plate of said core having spaced apart openingstherein which receive the opposite end of said plurality of tubes inposition within said two part housing,

inserting an end plate in position against said second end plate andlocking the same in position to thereby retain said first and second endplates and spacing members and bafiles intermediate said first andsecond end plates in spaced apart relationship,

placing said two part housing on a side thereof with the loading portsthe-rein facing upward,

pouring pellet material through each of said loading ports to fill thechamber communicating therewith, inserting plugs in said loading portsto retain the pellet material within the chambers, subjecting thefixture which is coated with a material to prevent adherence of brazingmaterial thereto and the heat exchanger core which is coated with abrazing material to a brazing operation whereby the component sectionsof the heat exchanger core are brazed together to form a unitized heatexchanger core, and

disassembling the two part housing and end plate secured thereto topermit removal of the unitized heat exchanger core therefrom.

4. A method of making a tube type brazed heat exchanger core having endplates and battles intermediate the end plates through which a pluralityof spaced apart tubes extend and which define a plurality ofcompartments adapted to be filled with pellet material comprising thesteps of:

providing a fixture having a two part housing removably secured togetherto form a cylindrical cavity closed at one end by an end plate removablysecured to the two part housing and provided with a plurality of spacedapart loading ports in the sidewall of the two part housing,

inserting a first end plate of the core in said two part housing inposition against a plurality of locating pins extending from said endplate secured to said two part housing, inserting one end of theplurality of tubes into associated spaced apart openings in said firstend plate,

inserting the spacing members and bafiles spaced apart by the spacingmembers in order longitudinally along said plurality of tubes withinsaid two part housing to define the plurality of compartments separatedby said baffles and communicating with said plurality of loading ports,

inserting a second end plate of the core having spaced apart openingstherein adapted to receive the opposite end of said plurality of tubesin position within said two part housing,

inserting an end plate in position against said second end plate andlocking the same in position to thereby retain said first and second endplates, spacing members and bafiles in spaced apart relationship withinsaid two part housing,

placing said two part housing on a side thereof with the loading portstherein facing upward,

pouring pellet material through each of said loading ports to fill thecompartment communicating therewith,

7 8 inserting a plug in each of said loading ports to retain curedthereto to permit removal of the unitized heat the pellet materialwithin the associated compartexchanger core therefrom. ment, ReferencesCited by the Examiner subjecting the fixture which is coated with amaterial to prevent adherence of brazing material thereto and 5 UNITEDSTATES PATENTS the heat exchanger core which is coated with a braz-2,242,985 5/ 1941 Feuneft 24996 ing material to a brazing operationwhereby said 214011797 6/1946 Rasmussenfirst and second end plates,baffles, spacing members, 2,443,574 6/1948 Burnstubes and pelletmaterial are brazed together to form 2686957 8/1954 Koerper' a unitizedheat exchanger core, and 10 WHITMORE A. WILTZ, Primary Examiner.disassembling the two part housing and end plates se- J D, HOBART, E i

3. A METHOD OF MAKING A TUBE TYPE BRAZED HEAT EXCHANGER CORE HAVING ENDPLATES AND BAFFLES INTERMEDIATE THEREOF THROUGH WHICH A PLURALITY OFTUBES EXTEND AND WHICH DEFINE A PLURALITY OF COMPARTMENTS ADAPTED TO BEFILLED WITH PELLET MATERIAL COMPRISING THE STEPS OF: PROVIDING A FIXTUREHAVING A TWO PART HOUSING REMOVABLY SECURED TOGETHER TO FORM A CAVITYCLOSED AT ONE END BY AN END PLATE REMOVABLY SECURED TO THE TWO PARTHOUSING AND PROVIDED WITH A PLURALITY OF LOADING PORTS FORMED IN THESIDEWALL THEREOF, PLACING THE TWO PART HOUSING UPRIGHT ON THE CLOSED ENDTHEREOF, INSERTING A FIRST END PLATE OF SAID CORE IN POSITION WITHINSAID TWO PART HOUSING AND INSERTING ONE END OF THE PLURALITY OF TUBES INSPACED APART OPENINGS FORMED IN SAID FIRST END PLATE, INSERTING SPACINGMEMBERS AND BAFFLES SPACED APART BY SAID SPACING MEMBERS IN ORDERLONGITUDINALLY WITHIN SAID TWO PART HOUSING TO DEFINE THE PLURALITY OFCOMPARTMENTS SEPARATED BY SAID BAFFLES AND COMMUNICATING WITH SAIDLOADING PORTS, INSERTING A SECOND END PLATE OF SAID CORE HAVING SPACEDAPART OPENINGS THEREIN WHICH RECEIVE THE OPPOSITE END OF SAID PLURALITYOF TUBES IN POSITION WITHIN SAID TWO PART HOUSING, INSERTING AN ENDPLATE IN POSITION AGAINST SAID SECOND END PLATE AND LOCKING THE SAME INPOSITION TO THEREBY RETAIN SAID FIRST AND SECOND END PLATES AND SPACINGMEMBERS AND BAFFLES INTERMEDIATE SAID FIRST AND SECONE END PLATES INSPACED APART RELATIONSHIP, PLACING SAID TWO PART HOUSING ON A SIDETHEREOF WITH THE LOADING PORTS THEREIN FACING UPWARD, POURING PELLETMATERIAL THROUGH EACH OF SAID LOADING PORTS TO FILL THE CHAMBERCOMMUNICATING THEREWITH, INSERTING PLUGS IN SAID LOADING PORTS TO RETAINTHE PELLET MATERIAL WITHIN THE CHAMBERS, SUBJECTING THE FIXTURE WHICH ISCOATED WITH A MATERIAL TO PREVENT ADHERENCE OF BRAZING MATERIAL THERETOAND THE HEAT EXCHANGER CORE WHICH IS COATED WITH A BRAZING MATERIAL TO ABRAZING OPERATION WHEREBY THE COMPONENT SECTIONS OF THE HEAT EXCHANGERCORE ARE BRAZED TOGETHER TO FORM A UNITIZED HEAT EXCHANGER CORE, ANDDISASSEMBLING THE TWO PART HOUSING AND END PLATE SECURED THERETO TOPERMIT REMOVAL OF THE UNITIZED HEAT EXCHANGER CORE THEREFROM.